This invention relates to an automatic performance device capable of adjusting the progress of automatic performance in response to the depression of keys by a performer.
Automatic performance devices in the prior art include those that automatically perform melody tones or other musical tones, automatically perform bass and chord tones, automatically perform arpeggio tones, and automatically perform rhythm tones on the basis of score data stored in a memory. Another automatic performance device in the prior art is in combination of some of the above devices. However, in all of these conventional automatic performance devices, automatic performance is carried out in the same tempo from start through end once it is initially set.
Accordingly, in an electronic musical instrument provided with such an automatic performance device, performance by depression of keys on the keyboards together with the automatic performance by the automatic performance device may cause such problem that key depression timing does not coincide with the progress of the automatic performance. Suppose that the key depression timing is faster than the progress of the automatic performance. In this case, if the next key is depressed in accordance with the length indicated by the next note on the music sheet (score), the above lead is maintained resulting again in time discrepancy between the manual and automatic performance in the next tone, and if the next key is depressed in coincidence with the timing of the automatic performance, the length of the tone produced becomes longer than what the corresponding note on the score represents since the tempo in the automatic performance is constant, i.e., independent of the key depression timing. In case that the key depression timing lags behind the tempo in the automatic performance, to the contrary, the equivalent lag remains if the next key depression timing is taken in accordance with the length of the next note, and the tone produced is shorter than what the corresponding note represents.
This independence of the automatic performance according to the prior art from the manual key depression timing may cause another problem. When a performer wishes to change the tempo during the performance, a time discrepancy between the key depression timing and the tempo of the automatic performance will inevitably occur. If the tempo of automatic performance can be adjusted in response to the key depression timing, the discrepancy will be eliminated and the key depression timing becomes coincident with the tempo in automatic performance. In an automatic performance device of the prior art, the tempo is adjusted by operating a tempo adjusting knob of the device. However, the tempo adjustment in the conventional device is practically impossible during performance since it involves highly delicate manupilation of the tempo adjusting knob.